I think we can all agree that our country would be much better off if Bernie Sanders were competing for the Democratic nomination against Gloria La Riva, Cornel West, or (why not?) Liza Featherstone. If that were the choice facing socialists in our fight to defeat Donald Trump, then it would make perfect sense for us to stand on the sidelines and watch these primaries play out. We could have a sensible debate over whether to break up the banks or simply nationalize them, for example, with full confidence that either outcome would pose a serious and enduring threat to capital.

And yet here we are, nearly a year away from the primary, and it already seems quite clear that Sanders will not be running against La Riva, Featherstone, or West. It also seems unlikely that he’ll be running against Warren, Buttigieg, or Beto — three opponents who remain mired in the single-digits even as they run as self-proclaimed capitalists.

Instead — if preference polling, favorability polling, first-day fundraising totals, and endorsements are any indication — Sanders’ primary opponent for the Democratic nomination will almost certainly be Joe Biden. He is winning by all of these measures, and has been for several months now, and usually by a significant margin. Sanders has managed to pass him in preference polling a few times, has annihilated him in various straw polls of uncertain legitimacy, and has built a sizable lead in overall fundraising — but none of this is enough to make him the frontrunner. And the rest of the field, meanwhile, is trailing far behind.

A persisting theory in circulation right now — call it the Biden Bubble — maintains that his lead is only temporary, and that his infamous propensity for gaffes, along with his record of bad votes and general creepiness, will eventually catch up with him.

Here’s my counter-scenario: none of this will matter. Biden will maintain a high floor of support propped up by Obama nostalgia, by disengaged voters who recognize his name but who will otherwise ignore the primaries until the final week, and by centrists who genuinely love his politics. As the primaries wear on and his opponents drop out, he’ll pick up a disproportionate number of anyone-but-Sanders voters who see him as their best bet, and of establishment players who need to bet on the winning horse for the sake of their careers. There will be a snowball effect, and sooner or later socialists will find themselves staring down the barrel of a Trump-or-Biden election.

The situation we find ourselves in is directly comparable to what faced Republicans in 2016: an unacceptable and eminently beatable frontrunner who is nevertheless guaranteed to win if the divided opposition can’t unite around another candidate. The GOP saw the writing on the wall quite early on; even Scott Walker had the sense to drop out and beg his opponents to rally against Trump. It was a classic collective action problem — for the greater good, most of the GOP candidates (as well as their base) would have to sacrifice their personal preferences. And yet even as Trump’s poll numbers soared and their own numbers tanked, also-rans like Jeb Bush and Marco Rubio insisted on staying in the race.

Socialism is the politics of collective action. If we can’t even do better than the GOP on this, we will lose. Every indicator we have says that Joe Biden is the candidate to beat, and every indicator we have points to one candidate as the best chance to beat him. It’s still Bernie.